This invention relates to screens for use in meat separators and particularly to a screen opening for preventing small pieces of bone and other hard material from passing through the screen along with the desired meat products.
Certain meat product and bone separator devices operate by forcing the combined meat products and bones against a screen. The screen has openings therethrough having a size sufficient for allowing the desired meat product to pass therethrough while blocking the large pieces of bone and other undesirable material to be removed from the meat products. To prevent the screen from plugging up, a blade or other cutting element is periodically passed across the screen surface and over the screen openings. The cutting element severs the meat products between the edge of the cutting element and the edge of the screen openings, thereby allowing more meat product material to enter the screen openings and forcing the severed part of the material on through the openings and out of the separator device. U.S. Pat. No. 5,041,055 shows an example of this type of meat separator. In the type of separator shown in this patent, an auger is used to compress material and also to cut the material at the surface of the screen.
Another type of separator includes a grinding plate or screen at an end of a conduit, and material is forced through the conduit and against the screen by an auger or other device. A blade at the end of the auger or a separate blade sweeps across the flat screen or grinding plate as the auger rotates. In this form of meat separator, channels formed in the grinder plate or screen guide bones and other hard material toward a central opening through which such material may pass.
Although bones and other hard material may be large enough not to pass through the screen openings in one piece, bones and other hard material may have corners or edges that may be forced into the portion of the screen openings adjacent the surface of the screen. When a bone piece or other hard material piece enters the screen openings adjacent to the surface of the screen and the cutting element passes over the opening, the cutting element may cut off a small portion of the bone or other hard material as is passes the screen opening. This small piece of bone or other undesirable material may then pass through the screen opening along with the desired meat products. The presence of these bone pieces or other hard material pieces lowers the quality of the separated meat products.